Sense Organs
1. Define the term sense organs and relate its importance.
A sense organ is an organ of the body which responds to external stimuli by
conveying impulses to the sensory nervous system.
Sense organs are important because they detect changes in the environment and
relays it to our nervous system.
2. Outline two functions of the five sense organs.
Sense Organ Function
Eye 1) Converts light to electric impulses for us
us to see.
2) Produce tears to supply nutrients to
the cornea, preventing infection and
healing damage to the eye.
Nose 1) Detects odours.
2) Helps in breathing.
Skin 1) Detects sensation example pain,
pressure and temperature.
2) Serves as a protection from invaders.
Ear 1) Detects sound waves.
2) Helps in balance.
Tongue 1) Detects tastes like sweet, sour, salty
and bitter.
2) Pushes the food to the back of the
mouth.
Table showing the functions of the sense organs
, 3. State the type of stimuli each organ detects and how it occurs.
Stimuli- Something that is done to an organ to have reaction. In other words, it is
a change in the environment.
Eye
The eye detects the stimulus of light. This occurs when you look at an object and the
light reflected from that object enters the eye. It passes through the cornea, which
is a transparent organ, then through the pupil, which is the black part of the eye.
The iris controls the amount of light entering the eye. The light then travels through
the lens which focuses on objects by changing its shape. The lens focuses it through
the vitreous humor which is a clear liquid, then to the retina, which has light
receptors called rods and cones which detects the light and sends it to the brain
through the optic nerve.
Nose
The nose detects the stimulus of scent. Odour enter the nose through two ways.
They are through the nostrils or behind the throat. The odour enters the nasal cavity
which has mucus and hairs to filter the air. The odour molecules land on the
epithelium which contains olfactory receptors that detect the smell and sends a
nerve impulse through the olfactory nerve to the brain saying what it smells.
1. Define the term sense organs and relate its importance.
A sense organ is an organ of the body which responds to external stimuli by
conveying impulses to the sensory nervous system.
Sense organs are important because they detect changes in the environment and
relays it to our nervous system.
2. Outline two functions of the five sense organs.
Sense Organ Function
Eye 1) Converts light to electric impulses for us
us to see.
2) Produce tears to supply nutrients to
the cornea, preventing infection and
healing damage to the eye.
Nose 1) Detects odours.
2) Helps in breathing.
Skin 1) Detects sensation example pain,
pressure and temperature.
2) Serves as a protection from invaders.
Ear 1) Detects sound waves.
2) Helps in balance.
Tongue 1) Detects tastes like sweet, sour, salty
and bitter.
2) Pushes the food to the back of the
mouth.
Table showing the functions of the sense organs
, 3. State the type of stimuli each organ detects and how it occurs.
Stimuli- Something that is done to an organ to have reaction. In other words, it is
a change in the environment.
Eye
The eye detects the stimulus of light. This occurs when you look at an object and the
light reflected from that object enters the eye. It passes through the cornea, which
is a transparent organ, then through the pupil, which is the black part of the eye.
The iris controls the amount of light entering the eye. The light then travels through
the lens which focuses on objects by changing its shape. The lens focuses it through
the vitreous humor which is a clear liquid, then to the retina, which has light
receptors called rods and cones which detects the light and sends it to the brain
through the optic nerve.
Nose
The nose detects the stimulus of scent. Odour enter the nose through two ways.
They are through the nostrils or behind the throat. The odour enters the nasal cavity
which has mucus and hairs to filter the air. The odour molecules land on the
epithelium which contains olfactory receptors that detect the smell and sends a
nerve impulse through the olfactory nerve to the brain saying what it smells.
